This invention relates to resinous condensation polymers of polycarboxylic acid compounds and aromatic diprimary amines comprising diamino-t-butylbenzenes. More particularly, this invention relates to soluble, film-forming polyamides, polyimides and polyamide-imides made using diamino-t-butylbenzenes which have amino groups meta or para to each other on a benzene ring.
Aromatic polyamides, polyimides and polyamide-imides have found extensive use in industry as fibers, composites, molded parts and dielectrics due to their toughness, flexibility, mechanical strength and high thermal stability, and, in the case of polyimides, their lower dielectric constant and high electrical resistivity. Such polymers have been used in both film and coating form as advanced materials for such uses as passivation and insulating coatings, interlevel dielectrics, die attach adhesives, flexible circuit substrates, and the like.
Although current polyamides, polyimides, and polyamide-imides made from, for instance, metaphenylenediamine, have the toughness, flexibility and thermal stability necessary to meet the rigorous processing and operating conditions required for certain uses, they do not exhibit the low dielectric constant and reduced moisture uptake shown by lower thermal stability polymers such as polyethylene and polytetrafluoroethylene. The latter polymers, however, are not useful despite their excellent dielectric and moisture uptake properties if thermal stability requirements are demanding. A further difficulty limiting the usefulness of polyethylene and polytetrafluoroethylene is due to to their insolubility in commercial organic solvents.
In addition, many of these applications require deposition of polymer from a solvent in order to form a thin film having the desired properties. Unfortunately, many polyamides, polyamide-imides and particularly polyimides are generally insoluble even in solvents like N-methyl pyrrolidone or N,N-dimethylacetamide, which inhibits their usefulness in important areas.